Polyimide precursor composition, polyimide film, and polyimide film / substrate laminate

Abstract

The invention relates to a polyimide precursor composition, a polyimide film, and a polyimide film / substrate laminate. A polyimide precursor composition which contains a polyimide precursor having a repeating unit represented by general formula (I) and at least one imidazole compound as an optional component in predetermined amounts. Using this polyimide precursor composition, it is possible to produce a polyimide film having improved light transmittance and adhesion in a polyimide film / base material laminate, while utilizing the advantages of aromatic polyimide films such as heat resistance and coefficient of linear thermal expansion. # imgabs0 #

Description

[0001] This application is a divisional application. The application number of its original application is 202380014149.2, the application date is July 27, 2023, and the invention title is "Polyimide Precursor Composition, Polyimide Film, and Polyimide Film / Substrate Laminate". Technical Field

[0002] The present invention relates to a polyimide precursor composition, a polyimide film, and a polyimide film / substrate laminate suitable for use in electronic device applications such as substrates for flexible devices. Background Art

[0003] Polyimide films are widely used in fields such as the electrical / electronic device field and the semiconductor field due to their excellent heat resistance, chemical resistance, mechanical strength, electrical properties, dimensional stability, etc. On the other hand, in recent years, with the advent of a highly information-based society, the development of optical materials such as optical fibers and optical waveguides in the optical communication field, and liquid crystal alignment films and protective films for color filters in the display device field has been promoted. In particular, in the display device field, as an alternative to glass substrates, research on lightweight and highly flexible plastic substrates and the development of displays that can be bent or curled are being actively carried out.

[0004] In displays such as liquid crystal displays or organic EL displays, semiconductor elements such as TFTs (thin film transistors) for driving each pixel are formed. Therefore, heat resistance and dimensional stability are required for the substrate. Polyimide films are expected to be used as substrates for display applications due to their excellent heat resistance, chemical resistance, mechanical strength, electrical properties, dimensional stability, etc.

[0005] Generally, flexible films are difficult to maintain flatness, so it is difficult to uniformly and precisely form semiconductor elements such as TFTs and fine wirings on flexible films. To solve this problem, for example, Patent Document 1 describes "a method for manufacturing a flexible device as a display device or a light receiving device, which includes the following steps: a step of coating a specific precursor resin composition on a carrier substrate and forming a film to form a solid polyimide resin film; a step of forming a circuit on the resin film; and a step of peeling the solid resin film having the circuit formed on its surface from the carrier substrate".

[0006] In addition, in Patent Document 2, as a method for manufacturing a flexible device, a method is disclosed that includes: after forming elements and circuits required for the device on a polyimide film / glass substrate laminate obtained by forming a polyimide film on a glass substrate, irradiating laser light from the glass substrate side to peel the glass substrate.

[0007] In the manufacturing methods of flexible electronic devices described in Patent Documents 1 and 2, in order to process a polyimide film / glass substrate laminate, appropriate adhesion is required between the polyimide film and the glass substrate.

[0008] Polyimide is usually colored yellowish-brown, so its use in transmissive devices such as liquid crystal displays with a backlight is limited. However, in recent years, polyimide films with excellent light transmittance in addition to mechanical and thermal properties have been developed, and the expectation for their use as substrates for displays has further increased. For example, Patent Document 3 describes a semi-alicyclic polyimide with excellent mechanical properties, heat resistance, etc. in addition to light transmittance.

[0009] On the other hand, as an aromatic polyimide for use as a flexible electronic device substrate, for example, Patent Documents 4 and 5 disclose a polyimide that uses a diamine component containing a fluorinated aromatic diamine such as 2,2'-bis(trifluoromethyl)benzidine (TFMB). In addition, for this use, Patent Documents 6, 7, and 8 disclose examples of using a diamine component containing an aromatic diamine compound containing an ester bond. Polyimides containing an aromatic diamine compound containing an ester bond are also known for use in copper-clad laminates (for example, Patent Document 9) and for forming release layers (Patent Document 10). In addition, Patent Documents 11 to 15 also disclose examples of using a diamine component containing an aromatic diamine compound containing an ester bond.

[0010] Prior Art Documents

[0011] Patent Documents

[0012] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-202729

[0013] Patent Document 2: International Publication No. 2018 / 221607

[0014] Patent Document 3: International Publication No. 2012 / 011590

[0015] Patent Document 4: International Publication No. 2009 / 107429

[0016] Patent Document 5: International Publication No. 2019 / 188265

[0017] Patent Document 6: Japanese Patent Application Laid-Open No. 2021-175790

[0018] Patent Document 7: International Publication No. 2017 / 051827

[0019] Patent Document 8: Chinese Patent Application Publication No. 110003470

[0020] Patent Document 9: Japanese Patent Application Laid-Open No. 2021-195380

[0021] Patent Document 10: WO 2016 / 129546

[0022] Patent Document 11: WO 2021 / 261177

[0023] Patent Document 12: US Patent Application Publication No. 2022 / 0135797 Specification

[0024] Patent Document 13: Japanese Patent Application Laid-Open No. 7-133349

[0025] Patent Document 14: Japanese Patent Application Laid-Open No. 2020-164704

[0026] Patent Document 15: US Patent Application Publication No. 2021 / 0017336 Specification SUMMARY OF THE INVENTION

[0027] PROBLEM TO BE SOLVED BY THE INVENTION

[0028] In recent years, the film-forming method of TFTs has been continuously improved, and the film-forming temperature has been continuously lowered compared to the past. However, high-temperature treatment is still required in specific processes. In addition, the larger the process margin, the better the yield. Therefore, it is preferable that the heat resistance of the substrate film is as high as possible. Although aromatic polyimides have problems in terms of coloring, they generally have excellent heat resistance. Therefore, if coloring can be reduced as much as possible, it may be possible to use them as substrates for display applications.

[0029] In particular, in smartphones equipped with an in-screen camera, light passes through the display and reaches the camera. Therefore, a high light transmittance is required for the polyimide film for this display, especially in the sensitivity region of the sensor. In addition, for example, in order to prevent whitening of the bent portion in a flexible display that can be bent, a high elastic modulus is required.

[0030] As described above, Patent Documents 4 and 5 disclose examples of the use of 2,2'-bis(trifluoromethyl)benzidine (TFMB). However, the present inventors have conducted research and found the following problems: In the process of forming an electronic device from a polyimide film / glass substrate laminate using TFMB as a monomer component, the polyimide film is likely to peel off from the glass substrate. After an inorganic thin film having a gas barrier function is formed on the polyimide film / glass substrate laminate and the laminate is exposed to high temperature, peeling is likely to occur.

[0031] In addition, in the manufacture of flexible electronic devices, there is sometimes a process of cutting a large polyimide film / glass substrate laminate (including after element formation) into individual flexible electronic devices (intermediate products). If the adhesion between the polyimide film and the glass substrate is insufficient, peeling may sometimes occur between the polyimide film and the glass substrate in this process. The reason is considered to be that polyimide easily absorbs moisture, so it tries to absorb moisture in the atmosphere from the cut end face (the upper part is a barrier film) and expand, resulting in peeling in the case of weak adhesion. In addition, in the laser peeling process of peeling the polyimide film from the glass substrate, when the adhesion strength between the polyimide film and the glass substrate is high, a small laser intensity is sufficient, so the change in the processed polyimide is small (no change). On the other hand, when the adhesion is weak, it is necessary to increase the laser intensity, so the processed polyimide sometimes discolors or the mechanical properties decrease. Therefore, extremely high adhesion, that is, peel strength, is required between the polyimide film and the glass substrate.

[0032] The above-mentioned documents 6 to 15 do not disclose the invention of the present application at all, and there are problems with polyimide films for use as flexible display substrates. Use examples of diamine components containing 4-aminophenyl-4-aminobenzoate (APAB; abbreviated as 4-BAAB in the present application) are described in Patent Documents 6 and 7, but they are insufficient in terms of film colorability. In Patent Document 8, a diamine compound with a specific structure is required, and it is insufficient in terms of film colorability and the elastic modulus of the film. The polyimide precursor compositions described in Patent Documents 11, 14, and 15 also require diamine compounds with specific structures and are not satisfactory in terms of uses such as flexible display substrates, such as haze. In addition, the polyimide films obtained from polyimide precursor compositions for other uses described in Patent Documents 9, 10, 12, and 13 do not meet the performance required for display uses including adhesion.

[0033] Therefore, an object of the present invention is to provide a polyimide precursor composition that utilizes the advantages of aromatic polyimide films such as heat resistance and linear thermal expansion coefficient, and at the same time manufactures polyimide films for uses in flexible electronic devices, particularly for flexible display substrates, such as light transmittance and adhesion in polyimide film / substrate laminates. Furthermore, an object of the present invention is to provide a polyimide film and a polyimide film / substrate laminate obtained from the polyimide precursor.

[0034] Means for Solving the Problems

[0035] The main disclosures of the present application are summarized as follows. The inventions regarding items A1 to A14 are referred to as Invention A series, and the inventions regarding items B1 to B12 are referred to as Invention B series.

[0036] The inventions of the Invention A series are as follows.

[0037] A1. A polyimide precursor composition, comprising: a polyimide precursor having a repeating unit represented by the following general formula (I); and at least one imidazole compound as an optional component in an amount of less than 1 mole relative to 1 mole of the repeating unit of the polyimide precursor;

[0038] [Chemical formula 1]

[0039]

[0040] (In general formula I, X 1 is a tetravalent aliphatic group or aromatic group, Y 1 is a divalent aliphatic group or aromatic group, R 1 and R 2 are independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, where

[0041] X 1 satisfies either (i) or (ii),

[0042] (i) contains 50 mol% or more of the structure represented by formula (1-1), and contains a total of 70 mol% or more of the structure represented by formula (1-1) and the structure represented by formula (1-2),

[0043] (ii) contains 70 mol% or more of the structure represented by formula (1-1) and / or the structure represented by formula (1-2),

[0044] [Chemical formula 2]

[0045]

[0046] Y 1 contains 70 mol% or more of the structure represented by formula (B).

[0047] [Chemical formula 3]

[0048]

[0049] Wherein, in the case of the above (ii), the following is the condition: at least one imidazole compound as an essential component is contained in an amount of 0.01 mole or more and less than 1 mole relative to 1 mole of the repeating unit of the polyimide precursor.

[0050] A2. The polyimide precursor composition according to item A1 above, wherein 60 mol% or more of X 1 is the structure represented by formula (1-1).

[0051] A3. The polyimide precursor composition according to any one of the preceding items, wherein Y 1More than 80 mol% thereof has a structure represented by formula (B).

[0052] A4. The polyimide precursor composition according to any one of the preceding items, wherein at least one imidazole compound is further contained in an amount of 0.01 mol or more and less than 1 mol per 1 mol of the repeating unit of the polyimide precursor.

[0053] A5. The polyimide precursor composition according to item A4 above, wherein the imidazole compound is at least one selected from the group consisting of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 1-phenylimidazole, imidazole, and benzimidazole.

[0054] A6. The polyimide precursor composition according to any one of the preceding items, wherein at least one silane compound having a Si-OR a structure (wherein R a is a hydrogen atom or a hydrocarbon group) is contained in an amount of more than 0 parts by mass and 60 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and the diamine compound in the production of the polyimide precursor composition.

[0055] A7. The polyimide precursor composition according to item A6 above, wherein the silane compound has the following formula:

[0056] (R a O) n Si(R b ) 4-n

[0057] (In the formula, n is an integer of 1 to 4, R a is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms, and R b is an alkyl group or an aryl group having 10 or less carbon atoms) The compound shown.

[0058] A8. A polyimide film obtained from the polyimide precursor composition according to any one of the preceding items.

[0059] A9. A polyimide film / substrate laminate, characterized in that it has:

[0060] A polyimide film obtained from the polyimide precursor composition according to any one of the preceding items; and

[0061] A substrate.

[0062] A10. The laminate according to item A9 above, wherein an inorganic thin film layer is further provided on the polyimide film of the laminate.

[0063] A11. The laminate according to any one of the preceding items, wherein the substrate is a glass substrate.

[0064] A12. A method for manufacturing a polyimide film / substrate laminate, comprising the following steps:

[0065] (a) A step of coating the polyimide precursor composition according to any one of the preceding items on a substrate; and

[0066] (b) A step of heat-treating the polyimide precursor on the substrate to form a polyimide film on the substrate.

[0067] A13. The method for manufacturing a laminate according to item A12 above, wherein after the step (b), it further comprises: (c) A step of forming an inorganic thin film layer on the polyimide film of the laminate.

[0068] A14. A method for manufacturing a flexible electronic device, comprising the following steps:

[0069] (d) A step of forming at least one layer selected from a conductor layer and a semiconductor layer on the inorganic thin film layer of the laminate manufactured in item A13 above; and

[0070] (e) A step of peeling the substrate from the polyimide film.

[0071] A15. A flexible electronic device comprising the polyimide film according to item A8 above.

[0072] A16. A flexible electronic device substrate composed of the polyimide film according to item A8 above.

[0073] The specification of this application also discloses inventions of a different type from the above, namely, inventions of Series B.

[0074] B1. A polyimide precursor composition containing:

[0075] A polyimide precursor whose repeating unit is represented by the following general formula (I); and

[0076] At least one imidazole compound in an amount of 0.01 mole or more and less than 1 mole relative to 1 mole of the repeating unit of the polyimide precursor.

[0077] [Chemical formula 4]

[0078]

[0079] (In the general formula I, X 1 is a tetravalent aliphatic group or aromatic group, Y 1 is a divalent aliphatic group or aromatic group, R 1and R 2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, provided that

[0080] X 1 contains 70 mol% or more of the structure represented by formula (1-1) and / or the structure represented by formula (1-2),

[0081] [Chemical formula 5]

[0082]

[0083] Y 1 contains 50 mol% or more of the structure represented by formula (B).

[0084] [Chemical formula 6]

[0085]

[0086] B2. The polyimide precursor composition according to item B1 above, wherein 40 mol% or more of X 1 is the structure represented by formula (1-1).

[0087] B3. The polyimide precursor composition according to any one of the preceding items, wherein 60 mol% or more of Y 1 is the structure represented by formula (B).

[0088] The polyimide precursor composition according to any one of the preceding items, wherein X 1 contains a total of 60 mol% or more of the structure represented by formula (1-1) and the structure represented by formula (1-2).

[0089] B5. The polyimide precursor composition according to any one of the preceding items, wherein the imidazole compound is at least one selected from the group consisting of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 1-phenylimidazole, imidazole, and benzimidazole.

[0090] B6. A polyimide film obtained from the polyimide precursor composition according to any one of the preceding items.

[0091] B7. A polyimide film / substrate laminate, characterized in that it has:

[0092] a polyimide film obtained from the polyimide precursor composition according to any one of the preceding items; and

[0093] a substrate.

[0094] B8. The laminate according to item B7 above, wherein an inorganic thin film layer is further provided on the polyimide film of the laminate.

[0095] B9. The laminate according to any one of the above-mentioned prior items, wherein the substrate is a glass substrate.

[0096] B10. A method for manufacturing a polyimide film / substrate laminate, which comprises the following steps:

[0097] (a) A step of coating the polyimide precursor composition according to any one of the above-mentioned prior items on a substrate; and

[0098] (b) A step of heat-treating the polyimide precursor on the substrate to laminate a polyimide film on the substrate.

[0099] B11. The method for manufacturing a laminate according to item B10 above, wherein after the step (b), there is further: (c) A step of forming an inorganic thin film layer on the polyimide film of the laminate.

[0100] B12. A method for manufacturing a flexible electronic device, which comprises the following steps:

[0101] (d) A step of forming at least one layer selected from a conductor layer and a semiconductor layer on the inorganic thin film layer of the laminate manufactured in item B11 above; and

[0102] (e) A step of peeling the substrate from the polyimide film.

[0103] Effects of the Invention

[0104] According to the present invention, it is possible to provide a polyimide precursor composition that can produce a polyimide film with improved light transmittance and adhesion in a polyimide film / substrate laminate while taking advantage of the characteristics of aromatic polyimide films such as heat resistance and linear thermal expansion coefficient. That is, the polyimide precursor composition of the present invention is most suitable for manufacturing polyimide films used as flexible display substrates. Furthermore, the present invention can provide a polyimide film, a polyimide film / substrate laminate obtained from the polyimide precursor.

[0105] In addition, according to one aspect of the present invention, it is possible to provide a polyimide precursor composition with more stable viscosity.

[0106] Furthermore, according to one aspect of the present invention, it is possible to provide a polyimide film and a polyimide film / substrate laminate obtained using the above polyimide precursor composition. Furthermore, according to another aspect of the present invention, it is possible to provide a method for manufacturing a flexible electronic device and a flexible electronic device using the above polyimide precursor composition. Detailed Embodiments

[0107] In the present application, a "flexible (electronic) device" refers to a device that is flexible itself. Generally, a semiconductor layer (such as transistors, diodes, etc. as components) is formed on a substrate to complete the device. The "flexible (electronic) device" is different from existing devices such as COF (Chip On Film) in which "hard" semiconductor components such as IC chips are mounted on an FPC (flexible printed circuit board). However, in order to operate or control the "flexible (electronic) device" of the present application, it is no problem to mount "hard" semiconductor components such as IC chips on a flexible substrate, or to make electrical connections, or to fuse them for use. Preferred flexible (electronic) devices that can be cited include flexible displays such as liquid crystal displays and organic EL displays, display devices such as electronic paper, solar cells, and light receiving devices such as CMOS.

[0108] More specifically, the term "flexible (electronic) device substrate" does not include a flexible wiring substrate (also referred to as a flexible substrate, flexible printed wiring board, etc.).

[0109] In the present application, the terms "for flexible (electronic) device substrate" and "for flexible display substrate" mean that when used in a polyimide film, the polyimide film itself is the main constituent element (or the substrate itself) of the substrate present in the final product, rather than a film or layer that does not exist in the final product or an auxiliary layer laminated on the substrate. If a specific example is given, the release layer is not the substrate.

[0110] The terms "for flexible (electronic) device substrate" and "for flexible display substrate" mean a polyimide precursor composition that directly manufactures the polyimide film for the above-mentioned substrate when used in a polyimide precursor composition. Specifically, by coating the polyimide precursor composition on a substrate and imidizing it, a polyimide film "for flexible (electronic) device substrate (including for flexible display substrate, the same hereinafter)" is obtained. Therefore, for example, in the case where two or more polyimide precursor compositions (intermediate compositions) are mixed and used for manufacturing a polyimide film, each polyimide precursor composition is not the "for flexible (electronic) device substrate" as defined in the present application. This is because the structure of the obtained polyimide film depends on the structure of the polyimide precursor composition that directly manufactures the polyimide film.

[0111] In addition, a copper-clad (or metal) laminated board is used to manufacture a flexible wiring substrate (flexible substrate, flexible printed wiring board), but since it does not manufacture a flexible (electronic) device, the polyimide precursor composition for manufacturing the copper-clad laminated board is not the polyimide precursor composition "for flexible (electronic) device substrate". It should be noted that the definitions of the above terms will sometimes be further elaborated in this specification.

[0112] Hereinafter, the polyimide precursor composition of the present invention will be described, and thereafter, the manufacturing method of the flexible electronic device will be described. Hereinafter, the description will be centered on Invention Series A, and for Invention Series B containing an imidazole compound as an essential component, it will be described in the item of the imidazole compound. As long as there is no contradiction, the description of Invention Series A is also applicable to the inventions of Invention Series B.

[0113] <<Polyimide Precursor Composition>>

[0114] The polyimide precursor composition for forming a polyimide film contains a polyimide precursor. In a preferred embodiment, the polyimide precursor composition further contains a solvent, and the polyimide precursor is dissolved in the solvent.

[0115] The polyimide precursor has a repeating unit represented by the following general formula (I).

[0116] [Chemical Formula 7]

[0117]

[0118] (In General Formula I, X 1 is a tetravalent aliphatic group or aromatic group, Y 1 is a divalent aliphatic group or aromatic group, and R 1 and R 2 are independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.)

[0119] Particularly preferred is a polyamic acid in which R 1 and R 2 are hydrogen atoms. When X 1 and Y 1 are aliphatic groups, the aliphatic group is preferably a group having an alicyclic structure.

[0120] In all the repeating units of the polyimide precursor, X 1 contains 50 mol% or more of the structure represented by formula (1-1), and contains a total of 70 mol% or more of the structure represented by formula (1-1) and the structure represented by formula (1-2). Here, formula (1-1) and formula (1-2) are structures derived from oxydiphthalic dianhydride (abbreviation: ODPA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (abbreviation: s-BPDA), respectively.

[0121] [Chemical Formula 8]

[0122]

[0123] In addition, Y 1More than 70 mol% thereof has the structure represented by the formula (B), that is, the structure derived from 4-aminophenyl-4-aminobenzoate (hereinafter abbreviated as 4-BAAB).

[0124] [Chemical Formula 9]

[0125]

[0126] By using a composition containing such a polyimide precursor, a polyimide film having high light transmittance and a high elastic modulus and improved adhesion of the polyimide film / substrate laminate can be produced. In addition, the obtained polyimide film is also excellent in properties such as heat resistance and low linear thermal expansion coefficient, which are the advantages of wholly aromatic polyimide films.

[0127] Regarding the polyimide precursor, the monomers (tetracarboxylic acid component, diamine component, other components) that provide X 1 and Y 1 in the general formula (I) will be described, and then the production method will be described.

[0128] In the present specification, the tetracarboxylic acid component includes tetracarboxylic acids, tetracarboxylic dianhydrides, and tetracarboxylic acid derivatives such as tetracarboxylic acid silyl esters, tetracarboxylic acid esters, and tetracarboxylic acid chlorides used as raw materials for producing polyimide. Although not particularly limited, it is convenient to use tetracarboxylic dianhydrides in production, and in the following description, examples of using tetracarboxylic dianhydrides as the tetracarboxylic acid component will be described. In addition, the diamine component is a diamine compound having two amino groups (-NH 2 ).

[0129] In addition, in the present specification, the polyimide film refers to both a film formed on a (carrier) substrate and present in the laminate and a film after peeling off the substrate. In addition, the material obtained by heat-treating (imidizing) the material constituting the polyimide film, that is, the polyimide precursor composition, is sometimes referred to as a "polyimide material".

[0130] <X 1 and the tetracarboxylic acid component>

[0131] As described above, (i) or (ii) is satisfied.

[0132] (i) In all the repeating units of the polyimide precursor, preferably 50 mol% or more of X 1 has the structure represented by the following formula (1-1) (derived from ODPA), and preferably the total amount of the structure represented by the formula (1-1) (derived from ODPA) and the structure represented by the formula (1-2) (derived from s-BPDA) is 70 mol% or more of X 1 .

[0133] (ii) On the condition that an imidazole compound described below is contained in an amount of 0.01 mole or more and less than 1 mole per 1 mole of the repeating unit of the polyimide precursor, the total amount of the structure represented by the formula (1-1) (derived from ODPA) and the structure represented by the formula (1-2) (derived from s-BPDA) is preferably X 1 is 70 mol% or more, and it may contain only either the structure of the formula (1-1) or the structure of the formula (1-2).

[0134] In addition, in either case of (i) and (ii), X 1 may be composed only of the structure of the formula (1-1) and the structure of the formula (1-2) (that is, the total of the structure of the formula (1-1) and the structure of the formula (1-2) is 100 mol%).

[0135] More preferably, 60 mol% or more of X 1 is the structure of the formula (1-1), which is advantageous in the case of requiring high light transmittance. Further more preferably, 70 mol% or more, further more preferably 80 mol% or more, further more preferably 90 mol% or more of X 1 is the structure of the formula (1-1), and it may also be 100 mol% of the structure of the formula (1-1).

[0136] In X 1 the total proportion of the structures of the formula (1-1) and the formula (1-2) is more preferably 75 mol% or more, further more preferably in the order of 80 mol% or more and 90 mol% or more, and further preferably 100 mol%. Therefore, the proportion of the structure of the formula (1-2) is 50 mol% or less, and it may also be 0%. By containing the structure of the formula (1-2), the linear thermal expansion coefficient and mechanical properties (such as elastic modulus) can be improved. By containing, for example, 10 mol% to 40 mol%, these properties and light transmittance can be improved in a balanced manner.

[0137] In the present invention, as X 1 , a tetravalent aliphatic group or aromatic group other than the structures represented by the formula (1-1) and the formula (1-2) (abbreviated as "other X 1 ") can be contained in an amount within the range that does not damage the effects of the present invention. As the aliphatic group, a tetravalent group having an alicyclic structure is preferred. Therefore, the tetracarboxylic acid component may contain "other tetracarboxylic acid derivatives" other than ODPA and s-BPDA in an amount of 30 mol% or less, more preferably 20 mol% or less, further more preferably 10 mol% or less based on 100 mol% of the tetracarboxylic acid component. An amount of 0 mol% of "other tetracarboxylic acid derivatives" is also a preferred embodiment.

[0138] In addition, X 1When the proportion of the structure of formula (1-1) (from ODPA) is less than 70 mol%, especially less than 60 mol%, it is also preferably contained in a proportion of more than 0 mol%, for example, 10 mol% or more and 30 mol% or less, for example, 20 mol% or less of "other X" 1 ". In this case, the particularly preferred "other X" 1 " preferably comes from a tetravalent group of a tetracarboxylic dianhydride having an aromatic ring containing a fluorine atom such as 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), or a tetravalent group of 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA). It should be noted that regarding "other X" 1 " not limited to this case, it is as follows.

[0139] As "other X" 1 ", a tetravalent group having an aromatic ring is preferred, and a tetravalent group having an aromatic ring with 6 to 40 carbon atoms is preferred.

[0140] As the tetravalent group having an aromatic ring, the following groups can be exemplified. Among them, the groups corresponding to formulas (1-1) and (1-2) are excluded.

[0141] [Chemical formula 10]

[0142]

[0143] (In the formula, Z 1 is either a direct bond or any of the following divalent groups.

[0144] [Chemical formula 11]

[0145]

[0146] Among them, Z 2 in the formula is a divalent organic group, and Z 3 , Z 4 are each independently an amide bond, an ester bond, a carbonyl bond, and Z 5 is an organic group containing an aromatic ring.)

[0147] As Z 2 , specifically, an aliphatic hydrocarbon group having 2 to 24 carbon atoms and an aromatic hydrocarbon group having 6 to 24 carbon atoms can be exemplified.

[0148] As Z 5 , specifically, an aromatic hydrocarbon group having 6 to 24 carbon atoms can be exemplified.

[0149] As the tetravalent group having an aromatic ring, the following tetravalent group is particularly preferred because the resulting polyimide film can balance high heat resistance and high light transmittance.

[0150] [Chemical Formula 12]

[0151]

[0152] (In the formula, Z 1 is a direct bond or a hexafluoroisopropylidene bond.)

[0153] Here, since the obtained polyimide film can have both high heat resistance, high light transmittance, and a low linear thermal expansion coefficient, Z 1 is more preferably a direct bond.

[0154] In addition, as a preferred group, in the above formula (9), Z 1 is the following formula (3A):

[0155] [Chemical Formula 13]

[0156]

[0157] a compound of a fluorene-containing group shown as such. Z 11 and Z 12 are each independently preferably the same and are a single bond or a divalent organic group. As Z 11 and Z 12 , an organic group containing an aromatic ring is preferred, and a structure shown by the formula (3A1) is preferred, for example.

[0158] [Chemical Formula 14]

[0159]

[0160] (Z 13 and Z 14 are independently a single bond, -COO-, -OCO-, or -O-. Here, when Z 14 is bonded to the fluorene group, it is preferred that Z 13 is -COO-, -OCO-, or -O- and Z 14 is a single bond structure; R 91 is an alkyl group or a phenyl group having 1 to 4 carbon atoms, preferably a methyl group, and n is an integer of 0 to 4, preferably 1.)

[0161] As a provider of X 1The tetracarboxylic acid component of the repeating unit of the general formula (I) which is a tetravalent group having an aromatic ring includes, for example, pyromellitic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 9,9-bis(3,4-dicarboxyphenyl)fluorene, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,4'-oxybisphthalic acid, bis(3,4-dicarboxyphenyl)sulfone, m-terphenyl-3,4,3',4'-tetracarboxylic acid, p-terphenyl-3,4,3',4'-tetracarboxylic acid, dicarboxyphenyldimethylsilane, bis(dicarboxyphenoxy)diphenyl sulfide, sulfonylbisphthalic acid, and their derivatives such as tetracarboxylic dianhydrides, tetracarboxylic silyl esters, tetracarboxylic esters, and tetracarbonyl chlorides. As for providing X 1 The tetracarboxylic acid component of the repeating unit of the general formula (I) which is a tetravalent group having a fluorine atom-containing aromatic ring includes, for example, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane and its derivatives such as tetracarboxylic dianhydrides, tetracarboxylic silyl esters, tetracarboxylic esters, and tetracarbonyl chlorides. The tetracarboxylic acid components can be used alone or in combination of two or more.

[0162] As for providing X 1The tetracarboxylic acid component of the repeating unit of formula (I) which is a tetravalent group having an alicyclic structure includes, for example, 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidenediphenoxy bisphthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1'-bi(cyclohexane)]-3,3',4,4'-tetracarboxylic acid, [1,1'-bi(cyclohexane)]-2,3,3',4'-tetracarboxylic acid, [1,1'-bi(cyclohexane)]-2,2',3,3'-tetracarboxylic acid, 4,4'-methylenebis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(propane-2,2-diyl)bis(cyclohexane-1,2-dicarboxylic acid), 4,4'-oxybis(cyclohexane-1,2-dicarboxylic acid), 4,4'-thiobis(cyclohexane-1,2-dicarboxylic acid), 4,4'-sulfonylbis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(dimethylsilanediyl)bis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(tetrafluoropropane-2,2-diyl)bis(cyclohexane-1,2-dicarboxylic acid), octahydrobicyclopentadiene-1,3,4,6-tetracarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, 6-(carboxymethyl)bicyclo[2.2.1]heptane-2,3,5-tricarboxylic acid, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]oct-5-ene-2,3,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-7-ene-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo[4.2.1.02,5]nonane-3,4,7,8-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane 5,5”,6,6”-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2c,3c,6c,7c-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic acid, decahydro-1,4-ethano-5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, tetradecahydro-1,4:5,8:9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid, and their derivatives such as tetracarboxylic dianhydrides, tetracarboxylic silyl esters, tetracarboxylic esters, tetracarbonyl chlorides. The tetracarboxylic acid component can be used alone, or two or more thereof can be used in combination.

[0163] <Y 1 and diamine component>

[0164] As described above, in all the repeating units in the polyimide precursor, it is preferable that 70 mol% or more of Y 1 has the structure of formula (B), and further preferably 80 mol% or more, still more preferably 90 mol% or more has the structure of formula (B), and it is also preferably 100 mol%.

[0165] In the present invention, as Y 1 , it is possible to contain a divalent aliphatic group or aromatic group other than the structure represented by formula (B) (abbreviated as "other Y 1 ") in an amount within a range that does not impair the effects of the present invention. That is, in addition to 4-aminophenyl-4-aminobenzoate (4-BAAB), the diamine component may further contain "other diamine compounds" in an amount of 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less based on 100 mol% of the diamine component. An amount of 0 mol% of "other diamine compounds" is also a preferred embodiment.

[0166] In addition, when the proportion of the structure of formula (1-1) (derived from 4-BAAB) is less than 90 mol%, particularly 80 mol% or less, it is also preferred to contain "other Y 1 " in a proportion exceeding 0 mol%, for example, 10 mol% or more and 20 mol% or less, for example, 15 mol% or less. Particularly preferred "other Y 1 " in this case is preferably a diamine compound having an ether bond in the molecular chain direction such as 4,4-oxydianiline (4,4-ODA) and 4,4'-bis(4-aminophenoxy)biphenyl (BAPB). It should be noted that "other Y 1 " not limited to this case is as described below.

[0167] When "other Y 1 " is a divalent group having an aromatic ring, a divalent group having an aromatic ring with 6 to 40 carbon atoms, more preferably 6 to 20 carbon atoms, is preferred.

[0168] Examples of the divalent group having an aromatic ring include the following groups.

[0169] [Chemical formula 15]

[0170]

[0171] (In the formula, W 1 is a direct bond or a divalent organic group, n 11 to n 13 each independently represent an integer from 0 to 4, and R 51 , R 52 , R 53 are each independently an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group, or a trifluoromethyl group.)

[0172] Examples of W 1, specifically, a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6) can be cited. Among them, the group corresponding to formula (B) is excluded.

[0173] [Chemical Formula 16]

[0174]

[0175] [Chemical Formula 17]

[0176]

[0177] (In formula (6), R 61 ~R 68 each independently represents either a direct bond or any one of the divalent groups represented by the above formula (5).)

[0178] Here, since the obtained polyimide can achieve both high heat resistance, high transparency, and a low linear thermal expansion coefficient, W 1 is particularly preferably a direct bond or one selected from the group consisting of the groups represented by the formulas: -NHCO-, -CONH-, -COO-, -OCO-. In addition, W 1 is also particularly preferably that R 61 ~R 68 is any one of the divalent groups represented by the above formula (6) which is a direct bond or one selected from the group consisting of the groups represented by the formulas: -NHCO-, -CONH-, -COO-, -OCO-.

[0179] In addition, as a preferred group, in the above formula (4), W 1 can be cited as the following formula (3B):

[0180] [Chemical Formula 18]

[0181]

[0182] a compound of a fluorene-containing group shown. Z 11 and Z 12 each independently is preferably the same and is a single bond or a divalent organic group. As Z 11 and Z 12 , an organic group containing an aromatic ring is preferred, and a structure represented by, for example, formula (3B1) is preferred.

[0183] [Chemical Formula 19]

[0184]

[0185] (Z 13 and Z 14 each independently is a single bond, -COO-, -OCO- or -O-, where Z14 When bonded to a fluorenyl group, Z is preferably 13 -COO-, -OCO- or -O- and Z 14 is a structure of a single bond; R 91 is an alkyl group having 1 to 4 carbon atoms or a phenyl group, preferably a phenyl group, and n is an integer of 0 to 4, preferably 1.)

[0186] As another preferred group, in the above formula (4), W 1 is a compound of a phenylene group, that is, a terphenyl diamine compound, and particularly preferably a compound in which all are para-bonded.

[0187] As another preferred group, in the above formula (4), W 1 is a structure of the first phenyl ring of the formula (6) in which R 61 and R 62 are 2,2-propylene groups.

[0188] As another preferred group, in the above formula (4), W 1 is a compound represented by the following formula (3B2).

[0189] [Chemical formula 20]

[0190]

[0191] As for providing Y as a divalent group having an aromatic ring 1Examples of the diamine component include p-phenylenediamine, m-phenylenediamine, benzidine, 3,3'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)benzidine, m-toluidine, 3,4'-diaminobenzanilide, N,N'-bis(4-aminophenyl)terephthalamide, N,N'-p-phenylenebis(p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis(4-aminophenyl)terephthalate, biphenyl-4,4'-dicarboxylic acid bis(4-aminophenyl) ester, p-phenylenebis(p-aminobenzoate), bis(4-aminophenyl)-[1,1'-biphenyl]-4,4'-dicarboxylate, [1,1'-biphenyl]-4,4'-diylbis(4-aminobenzoate), 4,4'-oxydianiline, 3,4'-oxydianiline, 3,3'-oxydianiline, p-methylenebis(phenylenediamine), 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, bis(4-aminophenyl)sulfone, 3,3'-bis(trifluoromethyl)benzidine, 3,3'-bis((aminophenoxy)phenyl)propane, 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis(4-(4-aminophenoxy)diphenyl)sulfone, bis(4-(3-aminophenoxy)diphenyl)sulfone, octafluorobenzidine, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,4-bis(4-aminophenylamino)-6-amino-1,3,5-triazine, 2,4-bis(4-aminophenylamino)-6-methylamino-1,3,5-triazine, 2,4-bis(4-aminophenylamino)-6-ethylamino-1,3,5-triazine, 2,4-bis(4-aminophenylamino)-6-anilino-1,3,5-triazine. As for providing Y 1The diamine component of the repeating unit of the general formula (I) which is a divalent group having an aromatic ring containing a fluorine atom includes, for example, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. In addition, as preferred diamine compounds, 9,9-bis(4-aminophenyl)fluorene, 4,4'-(((9H-fluorene-9,9-diyl)bis([1,1'-biphenyl]-5,2-diyl))bis(oxy))diamine, [1,1':4',1''-terphenyl]-4,4''-diamine, 4,4'-([1,1'-binaphthalene]-2,2'-diylbis(oxy))diamine can be mentioned. The diamine component can be used alone, or two or more thereof can be used in combination.

[0192] "When "other Y 1 " is a divalent group having an alicyclic structure, a divalent group having an alicyclic structure with 4 to 40 carbon atoms is preferred, and a divalent group having at least one aliphatic 4- to 12-membered ring, more preferably an aliphatic 6-membered ring is further preferred.

[0193] Examples of the divalent group having an alicyclic structure include the following groups.

[0194] [Chemical formula 21]

[0195]

[0196] (In the formula, V 1 , V 2 are each independently a direct bond or a divalent organic group, n 21 to n 26 each independently represent an integer of 0 to 4, and R 81 to R 86 are each independently an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group, or a trifluoromethyl group, and R 91 , R 92 , R 93 are each independently selected from the group consisting of the groups represented by the formulas: -CH 2 -, -CH=CH-, -CH 2 CH 2 -, -O-, -S-).

[0197] As V 1 , V 2 , specifically, a direct bond and the divalent group represented by the above formula (5) can be mentioned.

[0198] As Y which provides a divalent group having an alicyclic structure 1Examples of the diamine component include 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,3-diaminocyclobutane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, diaminobicycloheptane, diaminomethylbicycloheptane, diaminoxybicycloheptane, diaminomethoxybicycloheptane, isophoronediamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis(aminocyclohexyl)methane, bis(aminocyclohexyl) isopropylidene, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane. The diamine component can be used alone or in combination of two or more.

[0199] As the tetracarboxylic acid component and diamine component that provide the repeating unit represented by the above general formula (I), any one of aliphatic tetracarboxylic acids (especially dianhydrides) and / or aliphatic diamines other than alicyclic ones can be used, and its content is preferably less than 30 mol%, more preferably less than 20 mol%, and further preferably less than 10 mol% (including 0%) based on the total 100 mol% of the tetracarboxylic acid component and diamine component.

[0200] As "other Y" 1 ", by containing the structure represented by the formula (3B) and containing a diamine compound such as 9,9-bis(4-aminophenyl)fluorene as a specific compound, it is sometimes possible to increase Tg and reduce the phase difference (delay) in the film thickness direction.

[0201] In the present invention, regardless of the above description, the polyimide precursor composition sometimes used for manufacturing a polyimide film preferably does not contain a specific tetracarboxylic acid compound and / or a specific diamine compound, or a specific compound.

[0202] (a)H 2 N-Y 2 -N=N-Y 2 -NH 2 or H 2 N-Y 2 -NHNH-Y 2 -NH 2 (Y 2 is a divalent organic group) The diamine compound represented by is preferably very small (less than 5 mol in the repeating unit represented by the general formula (I)) or not contained.

[0203] (b) Surfactants and alkoxysilane compounds may be added, but it is also preferred not to contain surfactants, and the alkoxysilane compounds preferably do not contain compounds other than the compounds preferred in the present invention.

[0204] (c) It is preferably free of any of a diamine compound having a -SO 2 - group, a diamine compound having a fluorene structure, and a fluorinated diamine compound.

[0205] (d) A diamine compound containing a benzamide structure such as 3,5-diaminobenzamide is preferably not contained in an amount of 5 mol% or more in the diamine component, and more preferably not contained at all.

[0206] (e) It is preferably not contained in an amount of a diamine compound represented by the following formula in a molar ratio of 10:30 (=25:75) or more with respect to 4-BAAB, and even if contained, it is more preferably 15:85 or less, further preferably 10:90 or less, and still more preferably not contained at all in terms of molar ratio.

[0207] [Chemical formula 22]

[0208]

[0209] (f) It is preferably free of a combination of a tetracarboxylic dianhydride and a diamine compound that provides a repeating unit of the structure represented by the following formula.

[0210] [Chemical formula 23]

[0211]

[0212] (g) The diamine component preferably does not contain any of 2,2'-bis(trifluoromethyl)benzidine and 1,4-diaminocyclohexane.

[0213] (h) The diamine component preferably does not contain a diamine monomer containing a nitrogen heterocyclic structure in an amount of 3 mol% to 8 mol%, and more preferably does not contain it at all.

[0214] The polyimide precursor can be produced from the above-mentioned tetracarboxylic acid component and diamine component. Depending on the chemical structures taken by R 1 and R 2 The polyimide precursor used in the present invention (a polyimide precursor containing at least one of the repeating units represented by the above formula (I)) can be classified as:

[0215] 1) Polyamic acid (R 1 and R 2 are hydrogen);

[0216] 2) Polyamic acid ester (R 1 and R 2at least a part thereof is an alkyl group);

[0217] 3) 4) Polyamic acid silyl ester (R 1 and R 2 at least a part thereof is an alkylsilyl group).

[0218] Moreover, the polyimide precursor can be easily produced by the following production methods according to this classification. However, the production method of the polyimide precursor used in the present invention is not limited to the following production methods.

[0219] 1) Polyamic acid

[0220] The polyimide precursor can be suitably obtained as a polyimide precursor solution by the following reaction: in a solvent, a tetracarboxylic dianhydride as a tetracarboxylic acid component and a diamine component are reacted at a substantially equimolar ratio, preferably the molar ratio of the diamine component to the tetracarboxylic acid component [moles of diamine component / moles of tetracarboxylic acid component] is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, at a relatively low temperature of 120°C or lower while suppressing imidization.

[0221] There is no limitation. More specifically, the diamine is dissolved in an organic solvent or water, and while stirring, the tetracarboxylic dianhydride is slowly added to this solution, and it is stirred for 1 hour to 72 hours in the range of 0 to 120°C, preferably 5°C to 80°C, thereby obtaining the polyimide precursor. When reacting at 80°C or higher, the molecular weight varies depending on the temperature profile during polymerization, and in addition, imidization occurs due to heat, so it may not be possible to stably produce the polyimide precursor. The addition order of the diamine and the tetracarboxylic dianhydride in the above production method easily increases the molecular weight of the polyimide precursor, so it is preferred. In addition, the addition order of the diamine and the tetracarboxylic dianhydride in the above production method can be reversed, and since the precipitates are reduced, it is preferred. When using water as a solvent, it is preferred to add an imidazole such as 1,2-dimethylimidazole or a base such as triethylamine in an amount of preferably 0.8 times equivalent or more relative to the carboxyl group of the resulting polyamic acid (polyimide precursor).

[0222] 2) Polyamic acid ester

[0223] React a tetracarboxylic dianhydride with an arbitrary alcohol to obtain a dicarboxylic diester, and then react it with a chlorinating reagent (such as thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. Stir the diester dicarboxylic acid chloride and a diamine in the range of -20 °C to 120 °C, preferably -5 °C to 80 °C for 1 hour to 72 hours to obtain a polyimide precursor. When reacting at a temperature above 80 °C, the molecular weight varies depending on the temperature profile during polymerization, and imidization occurs through heat, so it may not be possible to stably produce the polyimide precursor. In addition, by using a phosphorus-based condensing agent, a carbodiimide condensing agent, etc. to perform dehydration condensation on the dicarboxylic diester and the diamine, the polyimide precursor can also be easily obtained.

[0224] The polyimide precursor obtained by this method is stable, so solvents such as water and alcohol can also be added for purification such as reprecipitation.

[0225] 3) Polyamide acid silyl ester (indirect method)

[0226] React a diamine with a silylating agent in advance to obtain a silylated diamine. Purify the silylated diamine by distillation or the like as needed. Then, dissolve the silylated diamine in a dehydrated solvent in advance, and slowly add a tetracarboxylic dianhydride while stirring, and stir in the range of 0 to 120 °C, preferably 5 to 80 °C for 1 hour to 72 hours to obtain a polyimide precursor. When reacting at a temperature above 80 °C, the molecular weight varies depending on the temperature profile during polymerization, and imidization occurs through heat, so it may not be possible to stably produce the polyimide precursor.

[0227] 4) Polyamide acid silyl ester (direct method)

[0228] Mix the polyamide acid solution obtained by the method of 1) with a silylating agent, and stir in the range of 0 to 120 °C, preferably 5 to 80 °C for 1 hour to 72 hours to obtain a polyimide precursor. When reacting at a temperature above 80 °C, the molecular weight varies depending on the temperature profile during polymerization, and imidization occurs through heat, so it may not be possible to stably produce the polyimide precursor.

[0229] As the silylating agent used in the methods of 3) and 4), when using a chlorine-free silylating agent, purification of the silylated polyamide acid or the obtained polyimide is not required, so it is preferred. Examples of the chlorine-free silylating agent include N,O-bis(trimethylsilyl)trifluoroacetamide, N,O-bis(trimethylsilyl)acetamide, and hexamethyldisilazane. For the reasons of being chlorine-free and low cost, N,O-bis(trimethylsilyl)acetamide and hexamethyldisilazane are particularly preferred.

[0230] In addition, in the silylation reaction of diamine in the method of 3), amine-based catalysts such as pyridine, piperidine, and triethylamine can be used to promote the reaction. This catalyst can be directly used as a polymerization catalyst for the polyimide precursor.

[0231] The solvent used in the preparation of the polyimide precursor is preferably water or aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and dimethyl sulfoxide. As long as it can dissolve the raw material monomer components and the resulting polyimide precursor, any type of solvent can be used without problem, so its structure is not particularly limited. As the solvent, water or amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and N-ethyl-2-pyrrolidone, cyclic ester solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, and α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, phenolic solvents such as m-cresol, p-cresol, 3-chlorophenol, and 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, and dimethyl sulfoxide are preferably used. In addition, other general organic solvents can also be used, namely phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirits, and naphtha-based solvents. It should be noted that two or more solvents can also be used in combination.

[0232] In the production of the polyimide precursor, there is no particular limitation, and the monomers and solvents are charged at a concentration such that the solid content concentration (mass concentration in terms of polyimide) of the polyimide precursor is, for example, 5% by mass to 45% by mass to carry out the reaction.

[0233] The logarithmic viscosity of the polyimide precursor is not particularly limited, and preferably the logarithmic viscosity in a 0.5 g / dL N-methyl-2-pyrrolidone solution at 30 °C is 0.2 dL / g or more, more preferably 0.3 dL / g or more, and particularly preferably 0.4 dL / g or more. When the logarithmic viscosity is 0.2 dL / g or more, the molecular weight of the polyimide precursor is high, and the mechanical strength and heat resistance of the resulting polyimide are excellent.

[0234] <Imidazole compound>

[0235] The polyimide precursor composition can contain at least one imidazole compound. The imidazole compound is not particularly limited as long as it is a compound having an imidazole skeleton, and examples thereof include 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 1-phenylimidazole, imidazole, and benzimidazole. A plurality of imidazole compounds can be used in combination. In a certain embodiment, the imidazole compound is preferably selected from imidazole compounds other than 1,2-dimethylimidazole, preferably dimethyl-substituted imidazole compounds other than 1,2-substitution, monomethyl-substituted imidazole compounds, and aromatic-substituted imidazole compounds, and particularly preferably 2-phenylimidazole, 1-phenylimidazole, imidazole, and benzimidazole.

[0236] The content of the imidazole compound in the polyimide precursor composition can be appropriately selected in consideration of the balance between the addition effect and the stability of the polyimide precursor composition. When the imidazole compound is added, the amount (total content) thereof is more than 0 mol and 0.01 mol or more, preferably 0.02 mol or more, relative to 1 mol of the repeating unit of the polyimide precursor in order to exert a certain degree of addition effect. On the other hand, from the aspect of the viscosity stability of the polyimide precursor composition, it is preferably in the range of less than 1 mol, more preferably less than 0.8 mol. The addition of the imidazole compound is effective for improving the light transmittance and the adhesion in a long-term high-temperature environment such as annealing treatment.

[0237] In particular, when the proportion of the structure of formula (1-1) (from ODPA) in X 1 is less than 90 mol%, especially less than 80 mol%, it is preferable to add an imidazole compound.

[0238] The imidazole compound can solve the problems in the case where the proportion of the structure of formula (1-1) (from ODPA) in X 1 is small, and in the case where the total proportion of the structure of formula (1-1) (from ODPA) and the structure of formula (1-2) (from s-BPDA) is small. When the imidazole compound is added, the proportion of the structure of formula (1-1) (from ODPA) in X 1 can be 0 mol% or more. That is, as long as the total proportion of the structure of formula (1-1) and the structure of formula (1-2) in X 1 is 70 mol% or more, any one kind can be included only, and the proportion of the structure of formula (1-1) can be zero.

[0239] After sorting out, as defined in 1. of the A series of inventions, the present application discloses a mode that does not require an imidazole compound (the case of condition (i)) and a mode that requires an imidazole compound (the case of condition (ii)).

[0240] In addition, the present application also discloses the following another invention that requires the addition of an imidazole compound, that is, the B series of inventions.

[0241] A polyimide precursor composition, which is a polyimide precursor composition containing a polyimide precursor having a repeating unit represented by the above general formula (I), wherein,

[0242] X 1 contains 70 mol% or more (preferably 80 mol% or more or 90 mol% or more) of the structure represented by formula (1-1) and / or the structure represented by formula (1-2),

[0243] Y 1 contains 50 mol% or more (preferably 60 mol% or more, 70 mol% or more or 80 mol% or more) of the structure represented by formula (B),

[0244] Further, at least one imidazole compound is further contained in an amount of 0.01 mol or more and less than 1 mol per 1 mol of the repeating unit of the above polyimide precursor.

[0245] In this other invention, elements and matters other than the above regulations are described according to the description of Invention A series in the text of this application.

[0246] <Silane compound>

[0247] It is also preferred to add a silane compound having a Si-OR a structure (R a is a hydrogen atom or a hydrocarbon group) as an additive to the polyimide precursor composition. The addition of the silane compound has the effect of improving the light transmittance.

[0248] R a is preferably a hydrocarbon group having 10 or less carbon atoms, preferably an alkyl group or an aryl group, particularly a straight-chain or branched alkyl group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably a methyl group or an ethyl group. For example, (R a O) n Si(R b ) 4-n (where n is an integer from 1 to 4) can be mentioned. R a As described above, n is preferably 1 to 3, more preferably 2 or 3. R b is a hydrocarbon group having 10 or less carbon atoms, preferably an alkyl group or an aryl group, more preferably an aryl group, and particularly preferably a phenyl group.

[0249] Specifically, examples include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxydimethylsilane, diethoxydimethylsilane, dimethoxydiphenylsilane, diethoxydiphenylsilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, trihexylmethoxysilane, trihexylethoxysilane, triphenylmethoxysilane, and triphenylethoxysilane. Two or more silane compounds can also be used in combination.

[0250] The addition amount of the silane compound can be appropriately selected in consideration of the addition effect. When adding the silane compound, the amount (total content) is more than 0 parts by mass relative to 100 parts by mass in total of the tetracarboxylic acid component and the diamine component. In order to exert a certain degree of addition effect, it is 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, still more preferably 0.5 parts by mass or more, and still more preferably 1 part by mass or more. From the aspect of the balance of physical properties, for example, it is 60 parts by mass or less, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, still more preferably 35 parts by mass or less, still more preferably 30 parts by weight or less, and still more preferably 25 parts by weight or less.

[0251] <Mixing of the polyimide precursor composition and "polyimide precursor composition for flexible electronic device substrate">

[0252] The polyimide precursor composition used in the present invention contains at least one of the above polyimide precursors and preferably contains a solvent. In addition, as described above, it preferably contains at least one imidazole compound.

[0253] As the solvent, the above solvents described as the solvents used in the preparation of the polyimide precursor can be used. Usually, the solvent used in the preparation of the polyimide precursor can be directly used, that is, used in the state of a polyimide precursor solution, but it can also be diluted or concentrated as needed. The imidazole compound (when added) is dissolved and present in the polyimide precursor composition. There is no particular limitation on the concentration of the polyimide precursor, and it is usually 5% by mass to 45% by mass in terms of the mass concentration of polyimide conversion (solid component concentration). Here, the mass of polyimide conversion means the mass when all repeating units are completely imidized.

[0254] The viscosity (rotational viscosity) of the polyimide precursor composition of the present invention is not particularly limited. Using an E-type rotational viscometer at a temperature of 25°C and a shear rate of 20 sec -1The rotational viscosity measured under the above conditions is preferably 0.01 to 1000 Pa·sec, more preferably 0.1 to 100 Pa·sec. Additionally, thixotropy can be imparted as needed. At viscosities within the above range, it is easy to handle during coating or film formation, and cratering is suppressed and the leveling property is excellent, thus a good coating film can be obtained.

[0255] The polyimide precursor composition of the present invention may contain, as needed, chemical imidizing agents (acid anhydrides such as acetic anhydride, amine compounds such as pyridine and isoquinoline), antioxidants, ultraviolet absorbers, fillers (inorganic particles such as silica), dyes, pigments, coupling agents such as silane coupling agents, primer, flame retardants, defoaming agents, leveling agents, rheology control agents (flow aids), etc. It should be noted that when imidizing the polyimide precursor composition of the present invention, thermal imidization is preferred, and in this case, it is preferred not to contain acid anhydrides such as acetic anhydride as chemical imidizing agents.

[0256] The polyimide precursor composition can be prepared by adding an imidazole compound or a solution of an imidazole compound to the polyimide precursor solution obtained by the method described above and mixing them. The tetracarboxylic acid component and the diamine component can be reacted in the presence of the imidazole compound.

[0257] The polyimide precursor composition of the present invention can be used for "flexible electronic device substrates (particularly preferably flexible display substrates. The same applies hereinafter)". As described above, in the present invention, the polyimide precursor composition for "flexible electronic device substrates" refers to a composition that is directly coated on a substrate as described below.

[0258] <<Manufacture of Polyimide Film / Substrate Laminate and Flexible Electronic Device>>

[0259] The polyimide film / substrate laminate can be manufactured using the polyimide precursor composition of the present invention (i.e., the polyimide precursor composition for flexible electronic device substrates). The polyimide film / substrate laminate can be manufactured through the following processes: (a) a process of coating the polyimide precursor composition on a substrate; (b) a process of heat-treating the polyimide precursor on the above substrate to manufacture a laminate (polyimide film / substrate laminate) having a polyimide film laminated on the above substrate. In addition to this, after forming a polyimide film on the substrate, as process (b2), it is also preferred to further have a process of forming an inorganic thin film on the surface of the polyimide film.

[0260] The manufacturing method of the flexible electronic device of the present invention uses the polyimide film / substrate laminate manufactured by the above-mentioned process (a) and process (b) (preferably further process (b2)), and further includes the following processes: namely, (c) a process of forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate; and (d) a process of peeling the substrate from the polyimide film.

[0261] First, in process (a), a polyimide precursor composition is cast onto a substrate, and imidization and desolvation are performed by heat treatment to form a polyimide film, thereby obtaining a laminate of the substrate and the polyimide film (polyimide film / substrate laminate).

[0262] As the substrate, a heat-resistant material is used, for example, a plate-shaped or sheet-shaped substrate such as a ceramic material (glass, alumina, etc.), a metal material (iron, stainless steel, copper, aluminum, etc.), a semiconductor material (silicon, compound semiconductor, etc.), or a film or sheet-shaped substrate of a heat-resistant plastic material (polyimide, etc.). Generally, a flat and smooth plate shape is preferred. Usually, a glass substrate such as soda-lime glass, borosilicate glass, non-alkali glass, or sapphire glass; a semiconductor (including compound semiconductor) substrate such as silicon, GaAs, InP, or GaN; a metal substrate such as iron, stainless steel, copper, or aluminum is used.

[0263] As the substrate, a glass substrate is particularly preferred. Glass substrates with a flat, smooth, and large area have been developed and can be easily obtained. There is no limitation on the thickness of the plate-shaped substrate such as a glass substrate. From the aspect of ease of processing, for example, it is 20 μm to 4 mm, preferably 100 μm to 2 mm. In addition, there is no particular limitation on the size of the plate-shaped substrate. One side (the long side in the case of a rectangle) is, for example, about 100 mm to about 4000 mm, preferably about 200 mm to about 3000 mm, and more preferably about 300 mm to about 2500 mm.

[0264] These substrates such as glass substrates may also have an inorganic thin film (such as a silicon oxide film) or a resin thin film formed on their surfaces.

[0265] There is no particular limitation on the casting method of the polyimide precursor composition onto the substrate, and examples thereof include known methods such as slit coating method, die coating method, blade coating method, spraying method, inkjet coating method, nozzle coating method, spin coating method, screen printing method, bar coating method, and electrodeposition method.

[0266] In step (b), the polyimide precursor composition is heat-treated on the substrate to convert it into a polyimide film, thereby obtaining a polyimide film / substrate laminate. The heat treatment conditions are not particularly limited, but it is preferably dried at a temperature range of 50°C to 150°C, and then treated at a maximum heating temperature of, for example, 150°C to 600°C, preferably 200°C to 550°C, and more preferably 250°C to 500°C.

[0267] The thickness of the polyimide film is preferably 1 μm or more, more preferably 2 μm or more, and further preferably 5 μm or more. When the thickness is less than 1 μm, the polyimide film cannot maintain sufficient mechanical strength. For example, when used as a substrate for a flexible electronic device, it is sometimes unable to fully withstand stress and is damaged. In addition, the thickness of the polyimide film is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 20 μm or less. If the thickness of the polyimide film becomes thicker, it sometimes becomes difficult to thin the flexible device. In order to maintain sufficient tolerance as a flexible device and further thin the film, the thickness of the polyimide film is preferably 2 μm to 50 μm.

[0268] In the present invention, the polyimide film / substrate laminate preferably has small warpage. The properties of the polyimide film can be evaluated by the residual stress between the polyimide film and the silicon substrate in the polyimide film / silicon substrate (wafer) laminate. The residual stress that can be achieved in the present invention will be described later.

[0269] The polyimide film in the polyimide film / substrate laminate may also have a second layer such as an inorganic thin film on the surface. Therefore, as step (b2), it is preferred to have a step of forming an inorganic thin film on the surface of the polyimide film formed on the substrate. The inorganic thin film is particularly preferred to function as a barrier layer for water vapor or oxygen (air). As the water vapor barrier layer, for example, a layer selected from silicon nitride (SiN x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y ), aluminum oxide (Al 2 O 3 ), titanium oxide (TiO 2 )、ZrO 2An inorganic film of an inorganic substance selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides. Generally, as a method for forming these thin films, physical vapor deposition methods such as vacuum evaporation, sputtering, and ion plating, and chemical vapor deposition methods (CVD: Chemical Vapor Deposition) such as plasma CVD and catalytic chemical vapor deposition (Cat-CVD) are known. In these film-forming methods including the CVD method, in order to improve the barrier function, after film formation, for example, high-temperature annealing is performed at 350°C to 450°C to densify the film. It should be noted that in this application, the "inorganic thin film" refers to two states before and after annealing. In the case of only indicating one of them, it is clearly indicated or clear from the context. Similarly, the "polyimide film / substrate laminate" refers to both cases with and without the "inorganic thin film".

[0270] The second layer may also be a plurality of layers. In this case, different types of inorganic thin films can be formed, and in addition, a resin film and an inorganic thin film can be combined. As an example of the latter, an example of a three-layer structure of a barrier layer / polyimide layer / barrier layer formed on the polyimide film in a polyimide film / substrate laminate can be cited.

[0271] In step (c), using the polyimide / substrate laminate obtained in step (b), at least one layer selected from a conductor layer and a semiconductor layer is formed on the polyimide film (including the case where an inorganic thin film or the like is laminated on the surface of the polyimide film). These layers can be directly formed on the polyimide film (including the case where the second layer is laminated), or can be formed indirectly after laminating other layers required for the device.

[0272] The conductor layer and / or the semiconductor layer are selected appropriately according to the elements and circuits required for the target electronic device. In step (c) of the present invention, when forming at least one of the conductor layer and the semiconductor layer, it is also preferable to form at least one of the conductor layer and the semiconductor layer on the polyimide film on which the inorganic film is formed.

[0273] The conductor layer and the semiconductor layer include both the case of forming over the entire surface of the polyimide film and the case of forming on a part of the polyimide film. The present invention can be transferred to step (d) immediately after step (c), or after forming at least one layer selected from the conductor layer and the semiconductor layer in step (c), further forming a device structure, and then transferred to step (d).

[0274] When manufacturing a TFT liquid crystal display device as a flexible device, for example, depending on requirements, a polyimide film having an inorganic film formed thereon over the entire surface is provided with, for example, metal wiring, a TFT using amorphous silicon or polycrystalline silicon, and a transparent pixel electrode. The TFT includes, for example, a gate metal layer, a semiconductor layer such as an amorphous silicon film, a gate insulating layer, wiring connected to the pixel electrode, and the like. In addition, a structure required for a liquid crystal display can be further formed by a known method. Further, a transparent electrode and a color filter can be formed on the polyimide film.

[0275] When manufacturing an organic EL display device, for example, depending on requirements, a polyimide film having an inorganic film formed thereon over the entire surface is provided with, for example, a TFT as needed in addition to a transparent electrode, a light-emitting layer, a hole transport layer, an electron transport layer, and the like.

[0276] In the present invention, since the preferred polyimide film is excellent in various properties such as heat resistance and toughness, there is no particular limitation on the method for forming a circuit, an element, and other structures required for the device.

[0277] Next, in step (d), the substrate is peeled from the polyimide film. The peeling method may be a mechanical peeling method in which peeling is physically performed by applying an external force, but since the adhesion of the polyimide film / substrate laminate of the present invention is excellent, peeling is particularly preferably performed by a so-called laser peeling method in which laser is irradiated from the substrate surface.

[0278] In the (semi) product using the polyimide film after peeling the substrate, a structure or component required for the device is further formed or assembled to complete the device.

[0279] As described above, a flexible electronic device including a polyimide film is completed, and in the flexible electronic device, the polyimide film functions as a flexible electronic device substrate.

[0280] It should be noted that as another manufacturing method of the flexible electronic device, after manufacturing the polyimide film / substrate laminate by the above step (b), the polyimide film may be peeled off, and at least one layer selected from a conductor layer and a semiconductor layer and a necessary structure may be formed on the polyimide film as in the above step (c) to manufacture a (semi) product using the polyimide film as a substrate.

[0281] <<Properties of the polyimide film in the polyimide film / substrate laminate>>

[0282] When manufacturing the above-described polyimide film / substrate laminate from the polyimide precursor composition of the present invention, since the adhesion between the polyimide film and the substrate is excellent, it is particularly preferably used for this purpose.

[0283] The ranges of the properties of the polyimide film achieved in the present invention are described below, and the preferred ranges are shown in the order of the first range, the second range, the third range, ···, the nth range.

[0284] The polyimide film produced from the polyimide precursor composition of the present invention has excellent adhesion to substrates such as glass substrates in addition to light transmittance, thermal properties, and heat resistance.

[0285] The adhesion can be evaluated by the peel strength. When the peel strength between the polyimide film and the substrate in the polyimide film / substrate laminate is measured according to JIS K6854-1, for example, in a 90° peel test at a tensile speed of 2 mm / minute, it is preferably 50 gf / cm (0.49 N / cm) or more (the first range), and more preferably 100 gf / cm (0.98 N / cm) or more (the second range), 150 gf / cm (1.47 N / cm) or more (the third range), 200 gf / cm (1.96 N / cm) or more (the fourth range), 300 gf / cm (2.94 N / cm) or more (the fifth range), 400 gf / cm (3.92 N / cm) or more (the sixth range), 500 gf / cm (4.9 N / cm) or more (the seventh range) in sequence. In addition, as the upper limit, it is usually 5 kgf / cm (49.0 N / cm) or less, preferably 3 kgf / cm (29.4 N / cm) or less. The peel strength is usually measured in air or the atmosphere.

[0286] As described above, the polyimide film / substrate laminate preferably has little warping, and the properties of the polyimide film can be evaluated by the residual stress between the polyimide film and the silicon substrate in the polyimide film / silicon substrate (wafer) laminate. The details of the measurement are described in Japanese Patent No. 6798633. Among them, the polyimide film is placed at 23 °C in a dry state. The residual stress evaluated thereby is preferably 20 MPa or less (the first range), and more preferably 15 MPa or less (the second range), 12 MPa or less (the third range), 10 MPa or less (the fourth range) in sequence.

[0287] In one embodiment of the present invention, when measured using a 10-μm-thick film, the light transmittance of the polyimide film at 450 nm is preferably 73% or more (the first range), and more preferably 74% or more (the second range), 75% or more (the third range) in sequence. In addition, when measured using a 10-μm-thick film, the yellowness index (YI) of the polyimide film is preferably 13 or less (the first range), and more preferably 12 or less (the second range), 11 or less (the third range), 10 or less (the fourth range), 9 or less (the fifth range) in sequence. In addition, the yellowness index (YI) is preferably 0 or more.

[0288] In addition, when measuring using a film with a thickness of 10 μm, the haze value of the polyimide film is preferably less than 1.0% (the first range), and more preferably 0.9% or less (the second range), 0.8% or less (the third range), 0.7% or less (the fourth range), 0.6% or less (the fifth range) in sequence.

[0289] The polyimide film of the present invention has an extremely low coefficient of linear thermal expansion (CTE). In one embodiment of the present invention, when measuring using a film with a thickness of 10 μm, the coefficient of linear thermal expansion of the polyimide film from 150 °C to 250 °C is preferably 27 ppm / K or less (the first range), and more preferably 25 ppm / K or less (the second range), 20 ppm or less (the third range), 15 ppm / K or less (the fourth range), 13 ppm / K or less (the fifth range) in sequence.

[0290] The polyimide film (or the polyimide constituting the same) of the present invention has excellent heat resistance, and the 1% weight loss temperature is preferably 512 °C or higher (the first range), and more preferably 515 °C or higher (the second range), 520 °C or higher (the third range), 522 °C or higher (the fourth range) in sequence.

[0291] In one embodiment of the present invention, the glass transition temperature (Tg) of the polyimide film (or the polyimide constituting the same) is preferably 350 °C or higher, more preferably 370 °C or higher, further more preferably 390 °C or higher, further more preferably 400 °C or higher, further more preferably 410 °C or higher, further more preferably 420 °C or higher, further more preferably 430 °C or higher, further more preferably 435 °C or higher, and most preferably 440 °C or higher.

[0292] The polyimide film of the present invention exhibits a very large elastic modulus. In one embodiment of the present invention, the elastic modulus of the polyimide film is preferably 6.5 GPa or higher (the first range), and more preferably 6.9 GPa or higher (the second range), 7.3 GPa or higher (the third range), 7.5 GPa or higher (the fourth range), 7.6 GPa or higher (the fifth range), 8.0 GPa or higher (the sixth range), 8.3 GPa or higher (the seventh range) in sequence. The elastic modulus can be, for example, a value obtained from a film with a thickness of about 8 μm to 12 μm.

[0293] Furthermore, in one embodiment of the present invention, the elongation at break of the polyimide film is preferably 10% or higher (the first range) when measuring using a film with a thickness of 10 μm, and more preferably 20% or higher (the second range), 25% or higher (the third range), 30% or higher (the fourth range) in sequence.

[0294] In addition, in another preferred embodiment of the present invention, the breaking strength of the polyimide film is preferably 200 MPa or more (the first range), and further preferably 250 MPa or more (the second range), 270 MPa or more (the third range), and 300 MPa or more (the fourth range) in sequence. The breaking strength can be, for example, a value obtained from a film with a film thickness of about 5 μm to 100 μm.

[0295] Regarding the properties of the polyimide film, it is preferred that the adhesion, light transmittance, and elastic modulus simultaneously satisfy the "preferred range", and it is particularly preferred that the linear thermal expansion coefficient and the 1% weight loss temperature also simultaneously satisfy the "preferred range".

[0296] The polyimide film having such properties, that is, the polyimide film for a flexible electronic device substrate itself has novelty and independently has patentability. Particularly preferred embodiments are as described below.

[0297] (1) The 450-nm light transmittance of the polyimide film is 74% or more (the second range), the elastic modulus is 6.9 GPa or more (the second range), preferably 7.3 GPa or more (the third range), and the linear thermal expansion coefficient and the elongation at break satisfy the above first range.

[0298] (2) The 450-nm light transmittance of the polyimide film is 75% or more (the third range), preferably 76% (the fourth range), the elastic modulus is 7.3 GPa or more (the third range), and the linear thermal expansion coefficient and the elongation at break satisfy the above first range.

[0299] (3) The 450-nm light transmittance of the polyimide film is 74% or more (the second range), preferably 75% or more (the third range), and the peel strength between the polyimide film and the substrate in the polyimide film / substrate laminate satisfies 200 gf / cm or more (the fourth range), preferably 300 gf / cm or more (the fifth range).

[0300] Other types of polyimides and individual polyimide films can also be manufactured using the polyimide precursor composition of the present invention. The manufacturing method is not particularly limited, and any known imidization method can be suitably used. The forms of the obtained polyimide can be suitably exemplified as films, coated films, powders, beads, molded bodies, foams, etc.

[0301] A single polyimide film can be manufactured using well-known methods. Representative methods are as follows: A polyimide precursor composition is cast and coated onto a substrate, and then, after heat imidization on the substrate, the polyimide film is peeled off. Alternatively, a polyimide precursor composition can be cast and coated onto a substrate, heated and dried to produce a self-supporting film, and then the self-supporting film is peeled off from the substrate. For example, the film is held by a tenter and heat imidized in a state where degassing can be performed from both sides of the film to obtain a polyimide film.

[0302] The thickness of a single polyimide film also depends on its use, and is preferably 1 μm or more, more preferably 2 μm or more, further preferably 5 μm or more, and for example, 250 μm or less, preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0303] Examples

[0304] The present invention will be further described below through examples and comparative examples. It should be noted that the present invention is not limited to the following examples.

[0305] In the following examples, evaluations were conducted by the following methods.

[0306] <Evaluation of Polyimide Precursor Composition>

[0307] [Viscosity Stabilization and Maximum Viscosity Retention Evaluation]

[0308] After polymerization, when the polyimide precursor composition is stored at 23 °C, the viscosity increases, reaches the maximum viscosity, and then decreases. When the maximum viscosity is reached, it is evaluated as "viscosity stabilization". In addition, although the viscosity decreases after reaching the maximum viscosity, the ratio of the viscosity 30 days after the day when the maximum viscosity is reached to the maximum viscosity is defined as the "maximum viscosity retention rate". A case where the viscosity is 50% or more relative to the maximum viscosity is evaluated as "〇", and a case where the viscosity is less than 50% is evaluated as "×".

[0309] It should be noted that the viscosity was measured using an E-type viscometer TVE-25 manufactured by Toki Sangyo Co., Ltd. with the measurement temperature set at 25 °C.

[0310] <Evaluation of Polyimide Film>

[0311] [Transmittance at 450 nm]

[0312] For polyimide films with a film thickness of approximately 10 μm in examples and comparative examples where the film thickness is not described, and for polyimide films with the described film thickness when the film thickness is described, the transmittance at 450 nm was measured using an ultraviolet-visible spectrophotometer / V-650DS (manufactured by JASCO Corporation).

[0313] [Yellowness Index (YI)]

[0314] Using a UV-visible spectrophotometer / V-650DS (manufactured by JASCO Corporation), in accordance with the standard of ASTM E313, measure the b* (= YI; yellowness index) of a polyimide film with a film thickness of 10 μm and a size of 5 cm square. The light source is D65, and the field of view angle is 2°.

[0315] [Haze]

[0316] Using a haze meter / NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.), in accordance with the standard of JIS K7136, measure the haze of the polyimide film.

[0317] [Coefficient of Thermal Expansion (CTE)]

[0318] Cut a polyimide film with a film thickness of about 10 μm into strips with a width of 4 mm to make test pieces. Use a TMA / SS6100 (manufactured by SII Nanotechnology Inc.) to cool from 400 °C to 50 °C under the conditions of a length between chucks of 15 mm, a load of 2 g, and a cooling rate of 20 °C / minute. Calculate the coefficient of thermal expansion from 150 °C to 250 °C from the obtained TMA curve.

[0319] [Temperature at 1% Weight Loss]

[0320] Use a polyimide film with a film thickness of about 10 μm as a test piece, and use a calorimeter measuring device (Q5000IR) manufactured by TA INSTRUMENTS to heat from 25 °C to 600 °C at a heating rate of 10 °C / minute in a nitrogen gas stream. From the obtained weight curve, set the weight at 150 °C to 100% and calculate the temperature at 1% weight loss.

[0321] [Peel Strength]

[0322] Use a TENSILON RTA-500 manufactured by ORIENTEC to measure the peel strength in the 90° direction under the condition of a tensile speed of 2 mm / minute in the atmosphere.

[0323] [Measurement of Residual Stress]

[0324] As a reference substrate for evaluating the polyimide film, use a 6-inch silicon wafer (625 μm thick, (100) substrate). Coat the polyimide precursor composition on the silicon wafer using a spin coater, and directly heat it from room temperature to the same temperature as in the examples and comparative examples in a nitrogen atmosphere (oxygen concentration below 200 ppm) for thermal imidization to obtain a polyimide film / reference substrate laminate. The film thickness of the polyimide film in the laminate is about 10 μm.

[0325] According to the description in Japanese Patent Publication No. 6798633, for the obtained polyimide film / silicon wafer laminate, the radius of curvature of warpage was measured at temperatures of 150 °C, 140 °C, 130 °C, 120 °C, and 110 °C using an FLX-2320 manufactured by KLA Tencor. The measurement was performed 20 times at each temperature, and the average value was obtained. In addition, the radius of curvature of the silicon wafer alone was also measured at the same temperature. Based on the obtained radius of curvature, the residual stress (S) at each temperature was calculated according to the following mathematical formula 1, and the residual stress at 23 °C was obtained by linear approximation based on the least squares method.

[0326] [Equation 1]

[0327]

[0328] Here,

[0329] E / (1-ν): Biaxial elastic modulus (Pa) of the substrate (reference base material: silicon wafer),

[0330] (100) silicon is 1.805E11 Pa,

[0331] h: Thickness of the substrate (m)

[0332] t: Thickness of the polyimide film (m)

[0333] R: Radius of curvature of the test specimen (m)

[0334] 1 / R = 1 / R 2 -1 / R 1

[0335] R 1 : Radius of curvature of the substrate (silicon wafer) alone before film formation

[0336] R 2 : Radius of curvature after film formation

[0337] S: Average value of residual stress (Pa)

[0338] [Elastic modulus, elongation at break, tensile strength]

[0339] A polyimide film with a thickness of about 10 μm was punched into a dumbbell shape according to IEC450 standard to prepare a test piece, and the initial elastic modulus, elongation at break, and tensile strength were measured using a TENSILON manufactured by ORIENTEC under the conditions of a gauge length of 30 mm and a tensile speed of 2 mm / minute.

[0340] <Raw materials>

[0341] The abbreviations of the raw materials used in the following examples are described below.

[0342] [Tetracarboxylic acid component]

[0343] PMDA: Pyromellitic dianhydride

[0344] DSDA: 3,3’,4,4’-Diphenylsulfone tetracarboxylic dianhydride

[0345] ODPA: 4,4’-Oxydiphthalic dianhydride

[0346] s-BPDA: 3,3’,4,4’-Biphenyltetracarboxylic dianhydride

[0347] 6FDA: 2,2-Bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride

[0348] [Diamine component]

[0349] 4-BAAB: 4-Aminophenyl-4-aminobenzoate

[0350] BAPB: 4,4’-Bis(4-aminophenoxy)biphenyl

[0351] 4,4-ODA: 4,4-Oxydianiline

[0352] [Imidazole compound]

[0353] 2-Pz: 2-Phenylimidazole

[0354] Bz: Benzimidazole

[0355] Im: Imidazole

[0356] 1-Pz: 1-Phenylimidazole

[0357] KBM-103: Phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0358] KBM-202SS: Diphenyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0359] HIVAC-F-5: 1,3,5-Trimethyl-1,1,3,5,5-pentaphenyltrisiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) [Solvent]

[0360] NMP: N-Methyl-2-pyrrolidone

[0361] The tetracarboxylic acid component and the diamine component are described in Table 1-1, and the structural formulas of the imidazole compounds are described in Table 1-2.

[0362] [Table 1-1]

[0363]

[0364] [Table 1-2]

[0365]

[0366] [Table 1-3]

[0367]

[0368] <Example 1>

[0369] [Preparation of polyimide precursor composition]

[0370] 2.28 g (10 mmol) of 4-BAAB was added to a reaction vessel purged with nitrogen, and 37.69 g of N-methyl-2-pyrrolidone was added in an amount such that the total mass of the monomers added (the sum of the diamine component and the carboxylic acid component) reached 12.5% by mass, and the mixture was stirred at room temperature for 1 hour. 3.10 g (10 mmol) of ODPA was slowly added to this solution. The mixture was stirred at room temperature for 6 hours to obtain a uniform and viscous polyimide precursor composition. The viscosity stability of the polyimide precursor composition is shown in Table 2.

[0371] [Manufacture of polyimide film / substrate laminate]

[0372] As the glass substrate, a 6-inch Eagle-XG (registered trademark) (500 μm thick) manufactured by Corning was used. The polyimide precursor composition was coated on the glass substrate using a spin coater, and directly heated from room temperature to 420 °C on the glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to carry out imidization by a thermal method, obtaining a polyimide film / substrate laminate. Regarding the peel strength, a test sample with a width of 5 mm was prepared from the obtained polyimide film / glass laminate for measurement. Regarding other film physical properties, the laminate was immersed in water at 40 °C (for example, in the range of 20 °C to 100 °C), the polyimide film was peeled off from the glass substrate, and after drying, the characteristics of the polyimide film were evaluated. The film thickness of the polyimide film was about 10 μm. The evaluation results are shown in Table 2.

[0373] <Examples 2 to 6, Comparative Examples 1 to 4>

[0374] In Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratio) shown in Table 2, and a polyimide precursor composition was obtained in the same manner as in Example 1 except for this. Thereafter, a polyimide film was manufactured in the same manner as in Example 1, and the film physical properties were evaluated.

[0375] <Examples 7, 11, Comparative Examples 6 to 8>

[0376] In Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratios) shown in Table 3, and reacted in the same manner as in Example 1 to obtain a polyimide precursor composition. Using the obtained polyimide precursor composition, the maximum heating temperature for imidization was changed to 450 °C, and a polyimide film was produced in the same manner as in Example 1 except for this, and the film physical properties were evaluated.

[0377] <Examples 8 to 10, Comparative Example 5>

[0378] In Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratios) shown in Table 3, and reacted in the same manner as in Example 1 to obtain a polyimide precursor solution.

[0379] 2-Phenylimidazole as an imidazole compound was dissolved in 4 times the mass of N-methyl-2-pyrrolidone to obtain a homogeneous solution with a solid component concentration of 20% by mass of 2-phenylimidazole. The solution of the imidazole compound was mixed with the above-synthesized polyimide precursor solution in such a manner that the amount of the imidazole compound was the amount described in Table 3 per 1 mol of the repeating unit of the polyimide precursor, and stirred at room temperature for 3 hours to obtain a homogeneous and viscous polyimide precursor composition.

[0380] After that, a polyimide film was produced in the same manner as in Example 7, and the film physical properties were evaluated. However, for Comparative Example 5, since the viscosity stability of the obtained polyimide precursor composition was poor, it was difficult to form a uniform polyimide film on the substrate, and thus the evaluation of the film physical properties could not be performed.

[0381] <Examples 12 to 25, Comparative Examples 9 and 10>

[0382] In Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratios) shown in Table 4 or 5, and reacted in the same manner as in Example 1 to obtain a polyimide precursor solution.

[0383] As the imidazole compound, the compound shown in Table 4 or 5 was changed, and the solution of the imidazole compound was mixed with the above-synthesized polyimide precursor solution in such a manner that its amount was the amount described in Table 4 or 5, and stirred at room temperature for 3 hours to obtain a homogeneous and viscous polyimide precursor composition.

[0384] After that, the maximum heating temperature for imidization was changed to 420 °C or 450 °C (as described in Table 4 or 5), and a polyimide film was produced in the same manner as in Example 1 except for this, and the film physical properties were evaluated. It should be noted that for Comparative Example 9, no imidazole compound was added.

[0385] This application summarizes the examples of condition (i) and the examples of condition (ii) specified in 1. of Invention A series as follows.

[0386] (i) 1 - 6, 7 - 11, 15 - 18, 19 - 25, 28

[0387] (ii) 8 - 10, 12 - 18, 19 - 25, 26, 27, 28

[0388] [Table 2]

[0389]

[0390] The unit of the amount of the imidazole compound is eq (moles per 1 mole of repeating unit).

[0391] [Table 3]

[0392]

[0393] The unit of the amount of the imidazole compound is (moles per 1 mole of repeating unit).

[0394] [Table 4]

[0395]

[0396] The unit of the amount of the imidazole compound is eq (moles per 1 mole of repeating unit).

[0397] [Table 5]

[0398]

[0399] The unit of the amount of the imidazole compound is eq (moles per 1 mole of repeating unit).

[0400] [Adhesion Test after Inorganic Thin Film Deposition]

[0401] On the polyimide film surface of the polyimide film / substrate laminate fabricated in the same manner as in the examples and comparative examples, SiOx and SiNx were each deposited to a thickness of 400 nm in sequence by plasma CVD. Subsequently, annealing treatment was performed at 430 °C for 60 minutes in an annealing furnace. After taking out from the annealing furnace, visual observation was carried out to observe the peeling between the polyimide film and the glass substrate, and between the polyimide film and the SiOx film. When no peeling was observed, it was evaluated as "○", and when peeling was observed in either case, it was evaluated as "×". The results are shown in Tables 2 - 5.

[0402] [Adhesion Test 2 after Inorganic Thin Film Deposition]

[0403] On the polyimide film surface of the polyimide film / substrate laminate manufactured in the same manner as in the examples and comparative examples, SiOx and SiNx were each formed into films with a thickness of 400 nm in sequence by plasma CVD method. Thereafter, annealing treatment was carried out at 430 °C for 8 hours in an annealing furnace. After taking out from the annealing furnace, visual observation was carried out to observe the peeling between the polyimide film and the glass substrate, and between the polyimide film and the SiOx film. When no peeling was observed, it was evaluated as "○", and when peeling was observed in any one of them, it was evaluated as "×". The results are shown in Table 6.

[0404] [Table 6]

[0405]

[0406] The unit of the amount of the imidazole compound is eq (moles per 1 mole of repeating unit).

[0407] Based on the above results, when the total of ODPA and s-BPDA in the tetracarboxylic acid component is 70 mol% or more and the proportion of ODPA is 50 mol% or more, the peel strength shows an extremely high value exceeding 400 gf / cm, and a significant increase in the light transmittance at 450 nm and a decrease in the yellowness index (YI) are observed. In addition, it was also confirmed that the addition of the imidazole compound is effective in increasing the light transmittance at 450 nm and decreasing the yellowness index (YI). In addition, when the imidazole compound is added in an amount of 0.01 mole or more and less than 1 mole, when the total of ODPA and s-BPDA in the tetracarboxylic acid component is 70 mol% or more (even if the proportion of ODPA is less than 50 mol%), the effects of high peel strength, high light transmittance at 450 nm and low yellowness index (YI) are confirmed.

[0408] [Examples of Adding Silane Compounds]

[0409] <Examples 29 to 34, 40 to 43, Reference Example 13>

[0410] Similar to Example 7, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratios) shown in Table 7, and reacted in the same manner as in Example 1 to obtain a polyimide precursor solution.

[0411] As the silane compound, the compounds and amounts (parts by mass relative to 100 parts by mass in total of the tetracarboxylic acid component and the diamine component) shown in Table 7 were mixed with the above-synthesized polyimide precursor solution, and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, the maximum heating temperature for imidization was set at 450 °C, and a polyimide film was manufactured in the same manner as in Example 1 except for this, and the film physical properties were evaluated.

[0412] <Examples 35 to 39>

[0413] Similar to Example 8 and the like, in Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratio) shown in Table 8, and reacted in the same manner as in Example 1. After obtaining the polyimide precursor solution, the solution of the imidazole compound was mixed with the polyimide precursor solution such that the amount of the imidazole compound was the amount described in Table 8. Regarding Examples 36 to 39, as the silane compound, the compounds and amounts (parts by mass relative to 100 parts by mass in total of the tetracarboxylic acid component and the diamine component) shown in Table 8 were mixed with the above-synthesized polyimide precursor solution, and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, the polyimide film was produced in the same manner as in Example 1 except that the maximum heating temperature for imidization was set to 450°C, and the film physical properties were evaluated. Note that, for comparison, no silane compound was added in Example 35, and the composition was the same as that of Examples 36 to 39 except for this, but Example 35 is an example of the present application.

[0414] <Examples 44 to 50>

[0415] Similar to Examples 7 and 8 and the like, in Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratio) shown in Table 9, and reacted in the same manner as in Example 1. After obtaining the polyimide precursor solution, regarding Examples 47 and 48, the solution of the imidazole compound was mixed with the polyimide precursor solution such that the amount of the imidazole compound was the amount described in Table 9. Regarding Examples 45, 46, 48 to 50, as the silane compound, the compounds and amounts (parts by mass relative to 100 parts by mass in total of the tetracarboxylic acid component and the diamine component) shown in Table 9 were mixed with the above-synthesized polyimide precursor solution, and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, the polyimide film was produced in the same manner as in Example 1 except that the maximum heating temperature for imidization was set to 450°C, and the film physical properties were evaluated. Note that Examples 44 and 47 are examples in which no silane compound was added for comparison, and they are examples of the present application.

[0416] <Examples 51 to 53>

[0417] Similar to Example 8 and the like, in Example 1, the tetracarboxylic acid component and the diamine component were changed to the compounds and amounts (molar ratio) shown in Table 10, and the reaction was carried out in the same manner as in Example 1. After obtaining the polyimide precursor solution, the solution of the imidazole compound was mixed with the polyimide precursor solution in such a way that the amount of the imidazole compound was the amount described in Table 10. Regarding Examples 52 and 53, as the silane compound, the compounds and amounts (parts by mass relative to 100 parts by mass in total of the tetracarboxylic acid component and the diamine component) shown in Table 10 were mixed with the above-synthesized polyimide precursor solution, and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, the maximum heating temperature for imidization was set to 450 °C, and a polyimide film was produced in the same manner as in Example 1 except for this, and the film physical properties were evaluated. It should be noted that Example 51 is an example in which no silane compound was added for comparison, and it is an example of the present application.

[0418] Regarding Examples 51 to 53, the peel strength test in the glass laminate and the measurement of the residual stress in the silicon wafer laminate were carried out in the same manner as in Example 1. Furthermore, the peeling between the polyimide film and the glass substrate and between the polyimide film and the SiOx film was observed in the same manner as in the above [Adhesion test 2 after inorganic thin film formation]. The measurement and evaluation results are shown in Table 10.

[0419] [Table 7]

[0420]

[0421] The content of the silane compound is parts by mass relative to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine.

[0422] [Table 8]

[0423]

[0424] Unit of the amount of the imidazole compound (moles per mole of repeating unit)

[0425] The content of the silane compound is parts by mass relative to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine.

[0426] [Table 9]

[0427]

[0428] Unit of the amount of the imidazole compound (moles per mole of repeating unit)

[0429] The content of the silane compound is parts by mass relative to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine.

[0430] [Table 10]

[0431]

[0432] The unit of the amount of the imidazole compound is eq (the number of moles per 1 mole of the repeating unit).

[0433] The content of the silane compound is in parts by mass relative to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine.

[0434] Referring to Table 7, compared with Example 7, in the examples in which the silane compounds (KBM-103 and KBM-202SS) were added, the light transmittance at 450 nm was further improved. In Reference Example 13, the light transmittance at 450 nm was also improved, but the decrease in the 1% weight loss temperature was large and the heat resistance was poor. Referring to Table 8, even in the system in which the imidazole compound was added, the improvement in the light transmittance at 450 nm could be confirmed by the addition of the silane compound.

[0435] The same tendency was also observed in Tables 9 and 10.

[0436] Industrial Applicability

[0437] The present invention can be suitably used for the manufacture of flexible electronic devices, such as flexible displays such as liquid crystal displays and organic EL displays, and display devices such as electronic paper, and light receiving devices such as solar cells and CMOS.

Claims

1. A polyimide precursor composition, comprising: A polyimide precursor having a repeating unit represented by the following general formula (I); At least one silane compound having an Si—OR structure, which is present in an amount of more than 0 part by mass and 60 parts by mass or less based on a total of 100 parts by mass of the tetracarboxylic dianhydride and the diamine compound when producing the polyimide precursor composition a structure Wherein, Si-OR a R in the structure a is a hydrogen atom or a hydrocarbon group; and As an optional component, at least one imidazole compound present in an amount of less than 1 mole per 1 mole of the repeating unit of the polyimide precursor, [Chemical formula 1] In general formula I, X 1 is a tetravalent aliphatic group or aromatic group, Y 1 is a divalent aliphatic group or aromatic group, R 1 and R 2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkylsilyl group having 3 to 9 carbon atoms, where X 1 satisfies either (i) or (ii), (i) containing 50 mol% or more of the structure represented by formula (1-1) and containing a total of 70 mol% or more of the structure represented by formula (1-1) and the structure represented by formula (1-2), (ii) containing 70 mol% or more of the structure represented by formula (1-1) and / or the structure represented by formula (1-2), [Chemical formula 2] Y 1 containing more than 70 mol% of the structure represented by formula (B) [Chemical formula 3] Wherein, in the case of (ii), the following is the condition: at least one imidazole compound as an essential component is contained in an amount of 0.01 mole or more and less than 1 mole per 1 mole of the repeating unit of the polyimide precursor.

2. The polyimide precursor composition according to claim 1, Characterized in that, X 1 More than 60 mol% thereof has the structure represented by the formula (1-1).

3. The polyimide precursor composition according to claim 1, Wherein, Y 1 80 mol% or more thereof has a structure represented by formula (B).

4. The polyimide precursor composition according to claim 1, Wherein, At least one imidazole compound is further contained in an amount of 0.01 mole or more and less than 1 mole per 1 mole of the repeating unit of the polyimide precursor.

5. The polyimide precursor composition according to claim 4, Characterized in that, The imidazole compound is at least one selected from the group consisting of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 1-phenylimidazole, imidazole and benzimidazole.

6. The polyimide precursor composition according to claim 1, Wherein, The silane compound is the following formula: (R a O) n Si(R b ) 4-n The compound shown, In the formula, n is an integer from 1 to 4, and R a is a hydrogen atom or a straight-chain or branched-chain alkyl group having 1 to 8 carbon atoms, and R b is an alkyl group or an aryl group having 10 or fewer carbon atoms.

7. A polyimide film obtained from the polyimide precursor composition according to claim 1.

8. A polyimide film / substrate laminate, Characterized in that, It has: A polyimide film obtained from the polyimide precursor composition according to claim 1; and A substrate.

9. The laminate according to claim 8, Wherein, An inorganic thin film layer is further provided on the polyimide film of the laminate.

10. The laminate according to claim 8 or 9, Wherein, The substrate is a glass substrate.

11. A method for manufacturing a polyimide film / substrate laminate, comprising the following steps: (a) A step of coating the polyimide precursor composition according to claim 1 on a substrate; and (b) A step of heat-treating the polyimide precursor on the substrate to laminate a polyimide film on the substrate.

12. The method for manufacturing a laminate according to claim 11, Wherein, After the step (b), there is further: (c) A step of forming an inorganic thin film layer on the polyimide film of the laminate.

13. A method for manufacturing a flexible electronic device, comprising the following steps: (d) A step of forming at least one layer selected from a conductor layer and a semiconductor layer on the inorganic thin film layer of the laminate manufactured in claim 10; and (e) A step of peeling the substrate from the polyimide film.

14. A flexible electronic device comprising the polyimide film according to claim 7.

15. A flexible electronic device substrate, which is composed of the polyimide film described in claim 7.

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